Spring-back chair



Nov. 13, 1956 a. F. HAMILTON SPRING-BACK CHAIR 2 Sheeizs--Sheei'l l Filed Sept. 24., 1951 Filed swept. 24. 1951 B. F. HAMILTON SPRING-BACK CHAIR 2 Sheets-Shaet 2 iin-mvg 35 q TTO IPA/E75.

United States Patent Olice 2,770,292 Patented Nov. 13, 195e SPRING-BACK CHAIR Bettis F. Hamilton, Columbus, Ind.; William S. Hamilton, executor of said Bertis `F. Hamilton, deceased Application September 24, 1951, Serial No. 247,969 4 Claims. (Cl. 155-157) This invention relates to chairs, and more particularly to an oce chair provided with .a spring-mounted back. In such chairs, the back is commonly carried by a backsupport which is pivotally connected to the chair-seat, and spring means are provided for yieldingly opposing rearward swinging of the back from a normal position. An object of the invention is to provide .a chair with a springmounted back which can be adjusted forwardly and rearwardly with respect to the chair-seat. Another object is to improve, simplify, and `cheapen the construction of spring-back chairs.

In carrying out the invention in its preferred form, I mount on the bottom of the chair-seat a pair of brackets each having a series of aligned holes for the reception of a pivot member. The back-support, which conveniently is formed of a single length of metal tubing, includes two parallel, generally horizontal portions which are respectively associated with the brackets `and are provided with holes `for the reception of the pivot members'. At a point spaced rearwardly from the brackets, lthe horizontal portions of `the back-support are interconnected by a bridge member provided with openings in which said horizontal portions are slidably received. Spring means, preferably adjustable, operates between' the seat and the bridge member to oppose rearward tilting `of the back-support about the pivot members.

The accompanying drawings illustrate the invention: Fig, l is' a side elevation of a chair; Fig. 2 is a vertical section `through the chair-seat on the line 2-2 of Fig. 4 showing the back-support in its normal position; Fig. 3 1s `a fragmental section similar to Fig. 2 showing the backsupport displaced rearwardly from its normal position; Fig. 4 is a bottom plan View of the chair-seat; and Figs. 5 and 6 are transverse vertical sections on `the lines 5-5 and 6-6 respectively of Fig. 4.

The chair shown in the drawing comprises a base 10 in lwhich `a vertical extending rod 11 is vertically adjustable, conveniently under the control of means such as 1s set `forth and described in my co-pen-ding application Serial No. 175,603, filed March 30, 1950, now Patent No. 2,673,590, granted March 30, 1954. The seat of the chair includes a cross-member 12 carrying a bearing 13 which receives' the upper end of the rod 11 to provide for rotation of the chair-seat about 4the axis of such rod.

In addition t-o the cross-member 12, the seat includes a pan 14 having a dished body portion and la downwardly extending peripheral flange 15. Padding 16 is disposed on the dished body portion of the pan 14 and is covered with fabric or other appropriate flexible sheet material which extends downwardly over the outer surface of the flange and is secured thereto adjacent the lower ange-edge.

The chair is provided with a back 20 supported on a back-support 21 conveniently formed yof a single length of metal tubing bent to provide two parallel horizontal portions 22 which extend forwardly below the seat and beneath the cross-member 12. Near their forward ends, lthe horizontal portions 22 of the back-support are pivotally 2 connected to brackets 23 secured in any convenient manner to the cross-member 12. Desirably, 'the brackets' 23 are channel-shaped in cross-section as will be clear from Fig. 5 and the horizontal portions 22 `of the backsupport are received respectively within those channels. The side walls of the brackets 23 are provided with series' of horizontally spaced holes 24 adapted to receive pivot members 25, which also extend 'through holes provided near `the front ends of the horizontal portions 22 of the back-support. The pivot members 25 support the back for swinging movement about the common axis of those pivot members; and by moving the pivot members from one set to another of the holes 24, the fore-and-aft position of the back 20 with respect to the seat can be varied.

Preferably, as indicated in Fig. 5, the pivot members 25 are straight end portions of wire members each of which also includes a bight 26, a second straight portion 27 parallel with the portion 25, and an ey'e 28 on the end of the portion 27. The straight portions 25 are adapted to be inserted into the brackets' 23 by movement from the side edges toward .the center Iof the chainseat, such inward movement being limited by engagement of the bights 26 with the outer walls of the brackets 23. A coiled tension spring 29 interconnects the eyes 28 to hold the pivot members in their operative position. Conveniently, each bight 26 is large enough to receive a finger, thus making it possible for the pivot members to be with drawn readily from one set of holes in the brackets and reinserted in another set. The spring 29 permits such withdrawal of the pivot members and serves to hold them in place in their new positions.

In rear of the cross-member 12 I provide a bridge member 31 which extends between and interconnects `the horizontal portions 22 of lthe backsupport. yConveniently, the bridge member 31 is `formed as a :sheet-metal stamping of inverted channel-shaped cross-section, the flanges of the channel being provided with :aligned anged holes in which the horizontal portions 22 of the 'backsupport are slida'ble. Between the two horizontal portions 22, `the pan 14 andthe web of the bridge member 31 are provided with aligned holes which receive a bolt 32 extending downwardly between and beyond the flanges of the bridge member where it is provided with an adjustable nut 33. A compression spring 34 surrounding the bolt 32 .and :acting `between the nut 33 and the bridge member opposes rearward swinging of the :back-support from a normal position which may be determined by the thickness of .a washer 35 inserted between the bridge member 31 and the seat-pan 14. Conveniently, the material of the seat-pan is oiTset downwardly' as indicated at 36 to provide a recess for reception of the head of the bolt 32.

The chair described lends itself readily to shipment and Vstorage in knocked-down condition; for, upon `withdrawal of the pivot members 25 from 'the brackets 33, the backsupport `and back .are readily separated from the seat `by sliding the horizontal portions 22 rearwardly through the bridge member. Attachment of the backsupport Lto the seat is effected with equal ease. By providing the brackets 23 with series of holes 24, it is possible to eltect easy and quick adjustment of the fore-andaft position of the back, the horizontal portions 22 of the back-support sliding within the `brackets 23 and within the holes in the flanges of the bridge member 31. Because the side walls of the brackets 23 embrace the horizontal portions 22 of the back-support, the pivot members 25 are relieved of stresses which they might otherwise be called upon to sustain.

I claim as my invention:

l. In a chair having a seat, `a back, a back-support including a generally horizontal portion extending beneath said seat and a generally vertical portion on which said back is mounted, means -for pivotally connecting the front end of said horizontal portion to said seat on a horizontal axis transverse to the seat, said means comprising a bracket secured lto said seat and a removable pivot pin extending through openings in said bracket and horizontal portion said bracket having a series of `openings in which said pivot pin is alternatively receivable, the openings of said series being spaced `apart fore-and-aft of said seat, and resilient means acting between the seat and back support and yieldingly opposing rearward movement of the back about said pivot pin.

2. In a chair, a seat structure and a back structure, said back structure lincluding a pair of parallel members of uni form cross-section extending generally horizontally beneath the seat structure, said seat structure being provided with `a pair of brackets respectively associated with said parallel members, each of said brackets comprising two vertical flanges extending longitudinally of ythe associated member for a distance materially greater than the Width of ythe member and closely receiving such member between them to confine movement of Athe member to a single vertical plane, pivot means connecting said members to ltheir respectively associated brackets for joint swinging movement about a common axis, and resilient means `opposing rearwardy swinging of said back structure about said axis.

3. The invention set forth in claim 2 with the addition that the anges of each 'bracket are provided with series of aligned holes spaced apart fore-and-aft of the seat, each of said members having ,a horizontal opening, said pivot means including a pair of pivot pins each insert-able through any pair of aligned holes in the bracket anges and through the opening in `the associated member.

4. The invention set forth in claim 3 with the addition of a bridge member rigidly interconnecting said members in Ithe rear of said brackets, said member-s being slidable longitudinally ofV `themselves in said bridge mem ber and said resilient means acting between the bridge member and the seat structure.

References Cited in the le of this patent UNITED STATES PATENTS 177,511 Hofmann May 16, 1876 669,253 Fraser Mar. 5, 1901 764,286 Gils'on July 5, 1904 872,498 Cleveland Dec. 3, 1907 1,184,902 Walton May 30, 1916 1,357,826 v Shaw Nov. 2, 1920 1,449,401 Headley Mar. 27, 1923 1,501,181 Peters et ial. Iu1y15, 1924 1,678,006 Headley July 24, 1928 1,691,033 Adams Nov. 13, 19,28 1,782,398 Alfreds Nov. 25, 1930 1,853,844 Bell t. Apr. 12, 1-932 2,307,621 Dorton Ian. 5, 1943 2,662,586 Cramer Dec. 15, 1953 FOREIGN PATENTS 510,613 Germany Oct. 21, 1930 

